Drivers of rainfall trends in and around Mainland Southeast Asia
Drivers of rainfall trends in and around Mainland Southeast Asia
Observational rain gauge/satellite and reanalysis datasets since the 1950s are evaluated for trends in mean and extreme rainfall in and around Mainland Southeast Asia (MSEA). Rain gauge data indicate strong increases exceeding 50% in both annual mean precipitation and various extreme precipitation indices over Vietnam and the northwestern part of the peninsula since 1979. The remote influence of ENSO may partially explain the recent precipitation trend toward a more intense regional hydrological cycle, in response to predominant La Niña states over recent decades. Increasing precipitation in MSEA is also associated with increased monsoon intensity in southeast Asia and a northward shift of the monsoon activity center toward MSEA over 1979–2018. Warming-driven evaporation increases were obtained over the adjacent seas typically feeding precipitation over MSEA associated with a shift toward predominantly positive phases of the two major natural climate variability modes of the tropical Indian Ocean, namely the Indian Ocean Dipole and the Indian Ocean Basin Mode. A moisture budget analysis using ERA5 re-analysis data showed increasing oceanic moisture transports along the typical winter and summer moisture pathways toward the MSEA. However, results show that during summer the major part of increased moisture from the oceanic moisture sources ends up as precipitation over the oceanic regions adjacent to MSEA with ERA5 not being able to produce the observed positive trends in summer continental precipitation. On the other hand, ERA5 reveals pronounced increases in winter precipitation over the MSEA, in accordance with rain-gauge data, associated with strongly increasing transport of moisture originated from the western tropical Pacific and the South China Sea.
Mainland Southeast Asia, evaporation, moisture budget, monsoon, rainfall, water cycle
Skliris, Nikolaos
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Marsh, Robert
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Haigh, Ivan
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Wood, Melissa
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Hirschi, Joel JM
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Darby, Stephen
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Quynh, Nguyen Phu
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Hung, Nguyen Nghia
2473441b-52b2-49fc-962d-d4e619c3e6ab
8 September 2022
Skliris, Nikolaos
07af7484-2e14-49aa-9cd3-1979ea9b064e
Marsh, Robert
702c2e7e-ac19-4019-abd9-a8614ab27717
Haigh, Ivan
945ff20a-589c-47b7-b06f-61804367eb2d
Wood, Melissa
3df4facc-304f-4664-848d-f6c808a23e56
Hirschi, Joel JM
c8a45006-a6e3-4319-b5f5-648e8ef98906
Darby, Stephen
4c3e1c76-d404-4ff3-86f8-84e42fbb7970
Quynh, Nguyen Phu
5b9fedbd-4566-4d28-a991-a203ec30c52c
Hung, Nguyen Nghia
2473441b-52b2-49fc-962d-d4e619c3e6ab
Skliris, Nikolaos, Marsh, Robert, Haigh, Ivan, Wood, Melissa, Hirschi, Joel JM, Darby, Stephen, Quynh, Nguyen Phu and Hung, Nguyen Nghia
(2022)
Drivers of rainfall trends in and around Mainland Southeast Asia.
Frontiers in Climate, 4, [926568].
(doi:10.3389/fclim.2022.926568).
Abstract
Observational rain gauge/satellite and reanalysis datasets since the 1950s are evaluated for trends in mean and extreme rainfall in and around Mainland Southeast Asia (MSEA). Rain gauge data indicate strong increases exceeding 50% in both annual mean precipitation and various extreme precipitation indices over Vietnam and the northwestern part of the peninsula since 1979. The remote influence of ENSO may partially explain the recent precipitation trend toward a more intense regional hydrological cycle, in response to predominant La Niña states over recent decades. Increasing precipitation in MSEA is also associated with increased monsoon intensity in southeast Asia and a northward shift of the monsoon activity center toward MSEA over 1979–2018. Warming-driven evaporation increases were obtained over the adjacent seas typically feeding precipitation over MSEA associated with a shift toward predominantly positive phases of the two major natural climate variability modes of the tropical Indian Ocean, namely the Indian Ocean Dipole and the Indian Ocean Basin Mode. A moisture budget analysis using ERA5 re-analysis data showed increasing oceanic moisture transports along the typical winter and summer moisture pathways toward the MSEA. However, results show that during summer the major part of increased moisture from the oceanic moisture sources ends up as precipitation over the oceanic regions adjacent to MSEA with ERA5 not being able to produce the observed positive trends in summer continental precipitation. On the other hand, ERA5 reveals pronounced increases in winter precipitation over the MSEA, in accordance with rain-gauge data, associated with strongly increasing transport of moisture originated from the western tropical Pacific and the South China Sea.
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fclim-04-926568
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e-pub ahead of print date: 8 September 2022
Published date: 8 September 2022
Additional Information:
Funding Information:
This work was funded by the UK's National Environment Research Council (NERC) and the National Foundation of Science and Technology Development (NAFOSTED-RCUK fund), Ministry of Science and Technology of Vietnam, through the grant CompFlood: Compound Flooding in coastal Vietnam (Grant No. NE/S003150/1). An earlier version of this work appeared online as a preprint in Research Square (Skliris et al., ).
Publisher Copyright:
Copyright © 2022 Skliris, Marsh, Haigh, Wood, Hirschi, Darby, Quynh and Hung.
Keywords:
Mainland Southeast Asia, evaporation, moisture budget, monsoon, rainfall, water cycle
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Local EPrints ID: 470337
URI: http://eprints.soton.ac.uk/id/eprint/470337
PURE UUID: 0ba611ab-b84a-444d-886d-b9c73215536b
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Date deposited: 06 Oct 2022 16:55
Last modified: 17 Mar 2024 03:56
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Author:
Melissa Wood
Author:
Joel JM Hirschi
Author:
Nguyen Phu Quynh
Author:
Nguyen Nghia Hung
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